The automation of immunoassay techniques has spawned a series of inventions without which such automated equipment would sometimes fail. The sensitivity of immunoassay techniques requires that unbound material be completely removed to permit detection. In practice this translates to providing washing techniques which are good to the parts per million level. When practiced manually, this washing procedure could be repeated several times or each individual wash could be extended over a greater period of time. The automation of this procedure makes soaking for an extended period of time impractical.
To overcome the difficulty of providing sufficient washing in a practical period of time, a wash probe has been developed to accomplish a high fluid throughput in a short time interval which vigorously injects the fluid to improve "wash" quality. The resulting probe is of substantial outside diameter, approaching the inside diameter of the test tubes in which such assays are typically performed. The use of this probe to remove unreacted reagents is the subject of our application Ser. No. 06/757,525 entitled METHOD AND APPARATUS FOR REMOVING UNREACTED COMPONENTS IN AUTOMATED IMMUNOASSAY TECHNIQUES, assigned to a common assignee.
While this increased probe size solved problems associated with automated washing procedures, the size of the probe in relation to the tube mouth made reliable entry into the tube a difficult problem. The wash probe, which is moved vertically by a shaft, must enter a series of tubes without getting caught on the edge of any tube. The test tubes are maintined in a rack which is not accurately made, and holds the tubes only loosely. Since the probe has a diameter close to that of the tube it must enter, an apparatus is needed to insure that the probe goes cleanly into the tube.
The subject invention provides a tube alignment apparatus which aligns the tube held loosely by the rack, centers the tube mouth relative to the probe and thereby permits effective and accurate insertion of a probe.
It is therefore an object of this invention to provide a tube alignment apparatus which permits accurate insertion of a probe, whose outside diameter is relatively large in comparison to the inside diameter of the receiving tube, into a receiving tube.
It is further an object of this invention to provide an inexpensive means to enable automated use of a large wash probe capable of accomplishing the degree of washing required in immunoassay techniques in a short period of time.
It is another object of this invention to provide a simple way to center test tube mouths which is effective and inexpensive.
It is a still further object of this invention to provide a device which requires no alignment or adjustment separate from the probe alignment since it is guided by the probe.
These, and further objects, shall become apparent to those skilled in the art by reference to this specification and the drawings to which it refers.